The invention relates to a microwave installation set for controlling the temperature of a heat bath. A process fluid used as a heat medium (heat bath) is to be heated to, and maintained at, a predetermined temperature with an accuracy of better than 1/100.degree. C. The heat bath is provided to maintain a well-defined temperature in containers filled with substrates under laboratory conditions.
Generally, closed (the heat bath is contained in a housing which can be closed) as well as open (openly accessible heat bath) temperature control arrangements are used. The conventional temperature control systems include resistance heating arrangements in the form of heating coils in order to achieve a uniform mixing of the heat bath medium by heat transfer and pumped circulation. A temperature controlled heat bath of 5 liter liquid having an electric power input of 2 kW requires about 20 minutes to reach a temperature of 90.degree. C.
It is the object of the present invention to provide an electromagnetically compatible (EMC) microwave-based system as an economical alternative to the conventional resistance heating and temperature control arrangement.